Quade

My clicking was coming from the right too. The stitch length adjustment is connected to the feed dog shaft so when the dog hit the plate, the shaft was jammed which actually made the reverse lever jump up and down and click. The fact yours clicks when you reduce the stitch length means that my idea was less likely for your issue. Because short stitch length keep the dogs more centered in the needle plate.

I'd unscrew the screws in the needle plate so, it's just sitting there then cycle the machine by hand and see if the feed dog is hitting the needle plate. My Juki was clicking at long stitch length and the problem was the feed dog was hitting the needle plate which being screwed down, pushed back on the feed mechanism. Once I unscrewed it, I could see the needle plate jumping as I cycled the machine. I had to adjust the feed dog so it didn't touch anymore.

1 - Under the cover plate on the front there's a screw that clamps the shaft that moved the needle fore and aft. 2 - This clamp is connected to an arm that goes down into the bottom where it bolts to a crank arm. The crank arm is adjustable. So you can make the needle movement match the feed dog movement. 3 - The shaft that goes to the crank arm also drives the feed-dogs. So it could be loose at the top under cover (though unlikely) loose at the crank or there could be slop in the linkage that drives the feed dog shaft. I'd probably flip it up so you can see the bottom, then, with the needle not engaging the dogs, move the needle forward and backwards and see if you can detect the slop. If the feed dogs move with the needle slop, I'd look at the mechanism and cam that moves that shaft. It's feed off the main shaft. The one with the belt on it.

You're kind of on your own. I never found a good disassembly and re-assembly manual. That said I completely disassembled and re-assembled my 211 (new version of the 111). It's not that hard. I'd take pictures of everything before I took anything off 1 - Line up the take up arm to it's highest point and note which Letter the timing belt is set to in the bottom. Some manuals say line up on A, some on B. You want to know before you take it apart. 2 - The upper shaft is sandwiched between the hand wheel and a counterweight on the other end of the machine. My counterweight had 2 set screws into the shaft. You ought to be able to release these set screws to release that end of the shaft. It's very similar to replacing the take up arm so, you might look at those instructions. 3 - Note the position of the clutched thing that drives the walking foot. Getting that timed properly took me the most time and I'm still not sure it's exactly right. Maybe see where it is in relation to the timing marks before you pull the belt. 4 - That spring loaded clutch thing that moves the walking feet has set screws into the shaft (I'm assuming the 111 is the same as the 211 here). There's two set screws which aren't the two next to pan head screws. There might be a spacer on the shaft on the needle side of this thing. It's got a set screw too. 5 - There's a set screw in the thing on the shaft that drives the bobbin winder (if yours is on top like the 211). 6 - The upper timing gear has two set screws into the shaft. One deep and one shallow. You need to note their position when you take them out. With all that loosened up, you ought to be able to slide the shaft out the hand wheel side. I found that if the foot driver spring retainer is too tight, it can squeeze the shaft. If you loosen them and the spring comes out, you'll probably have to pull the mechanism out of the machine and get the spring retainer back on on a bench. The spring is quite strong. This was just my experience taking one apart. There might be an easier way. I don't believe the timing gear will go through the casing so, the shaft has to be pulled through the gear. The shaft was keyed at the timing gear and at the counterweight that drives the takeup arm and needle side. The thing that drives the walking feet wasn't keyed. The manual seems to suggest you just eyeball it.

Is it really bad? I'm wondering if a good cleaning and rust removal could restore most of it. https://www.amazon.com/Evapo-Rust-Original-Water-based-Non-Toxic-Biodegradable/dp/B00GRSOJSS/ I've used this. Does a fantastic job. The rust just dissolves away. Cast iron is pretty tough. I'd probably get it apart, clean and inspect to see if you really need parts.

I just did this with my Singer 211. Powder coated the whole thing. It was a bit tedious getting the tuning working again. Particularly because the manuals are garbage. I feel it would be much easier if I did it again.

I really appreciate the response.

The sticker on my Singer 211A1121 says "135x17 long". The manuals I've looked at spec just 135x17. So I'm wondering if all 135x17's are the same length and just have different hole sizes? This machine is a bit of a Frankenstein. It once had a thread cutter and back step solenoid. When I got it, both were missing but, some parts of the mechanism are still there. I've seen other posts about this particular variant here but, not much information in people using them. I get the impression they came out of upholstery businesses.

I removed the brake from my motor. It was a simple process.

This is what I was hinting at too. My DDL-5550 is a great sewing machine. It'll even do relatively thick layers of cloth but I can tell the tension system is sort of at the limit. It works fine for making bags, repairing and making dog beds and even some light webbing work but, you can feel it groaning a bit at the thicker end.

A VFD lets you change the frequency of the AC in order to change the speed of the 3 phase motor. An "Inverter rated" motor is built to run at variable speeds. A standard motor might overheat when run at a non-standard frequency. So you can run a standard motor on a VFD as long as you're just putting out 60 hz and running the motor at the rated speed. The benefits of the VFD in this case would be slow start and braked stopping. Also you can remote control the VFD. I use the VFD on both the lathe and drill press to change the speed of the motor. It saves me from belt changes. Not knowing this box and motor, I had second thoughts about recommending the VFD. If the box simply turns the AC into DC and runs everything including the motor on DC, then a VFD would work fine. On the other hand if the box does tricky things with the AC, the VFD might not be a good idea. As someone else pointed out, the VFD doesn't like switches and such between it's output and the load. Easiest thing would be to just install a cheap servo.

I run my 3 phase lathe and drill press off a $200 VFD https://www.amazon.com/HKS-Variable-Frequency-Controller-Converter/dp/B09Q8JVTVN/ Here's a cheap one. 110v single phase to 220 3 phase. Instead of that, I'd install a 750 watt servo motor and simply not use the servo the machine came with. https://www.amazon.com/Consew-CSM3000-Sewing-Machine-Electric/dp/B01N1L1P7G/ It's a relatively simple install.

I'd get the part number off the box the wiring goes to and look up the part number. There should be a label on the machine that indicates the voltage too. I usually assume 3 hots and a ground is 3 phase. I have the DDL-5550 and installed a $150 servo motor. I'm not seeing a needle positioning system so, this servo might be overkill for this relatively basic machine. The 5550's are made for light to medium duty clothing. I wouldn't use one for leather or upholstery. They have a standard feed dog feeding system. Most have relatively short max stitch lengths too.

On a typical machine, when the manual foot lift is up, the tension disks on that end tensioner should be loose so any comparing of thread tension should be done with the foot down. With the foot up, the thread should pull through relatively easily. I notice you have the tensioner screwed all the way in. Makes me wonder if you're not factoring in the release when the manual lift is up. It's possible for the tensioner to be too far into the machine so the tension disk are always in released state even with the manual lift lever down. On my Juki, there's a little pin that connects to the lift lever which pushes the disks apart while threading. If the tensioner is set too deep into the machine, this pin will open the disks even with the lever down. The fact you see the tensioner move after you tighten it, suggests, you're running into an issue like this. I think you should loosen the tensioner to maybe 1/2 tension. Then unscrew the set screw that holds it in place. Then slide the tensioner in and out till you feel some contact. If you push it in more, does it release the disks?

They have non-staining oil for this purpose. My Juki collects oil on the needle. There's an oil pump that pumps into the hook and all the way into the front where the needle is. It collects over time. Once I wipe the needle, I don't notice it again till it sits for awhile. I agree that if you're not sewing things like vinyl quickly, you probably don't need it.

That manual makes me want to buy another Juki...

Haha. Happened to me. I was touching the knee lift slightly but it was enough to release the tension. So it sewed properly most of the time but occasionally I'd get a nest of thread.

What they recommend for tension is use a different color for top and bottom threads so you can see where the knot is.

I was thinking this from the picture too. Particularly the picture that shows the hook and needle. I was thinking it might be better to pull the two screws off so, and the cover plate so you can see the hook more easily. The hook is pretty deep on that pic. I wonder if the OP is timing off the wrong part of the hook? if you read section 8 of the manual, it's pretty much saying what I said. About the needle eye and hook placement. Needle to the bottom, starts going up, the hook should be right in line with the needle, 1.6 mm from the needle eye. Often there are timing marks on the needle bar. Bottom mark is used to set the needle bar length and the top is for where the needle and hook should intersect. This machine, it seems you set the needle bar length to get the timing position correct.

What's it not doing? 1- The needle and the hook need to pass next to each other as closely as possible without touching so, you might need to move the entire hook assembly towards or away from the needle. The hook actually passes inside the cutout on the needle. On my 211, there's two clamp screws and the actual gear needs to be loosened so I can move the hook either closer or farther to the needle. Then everything needs to be clamped down. If you know where the hook is, you automatically know the orientation of the needle. 2- The hook should be 1/16th of an inch above the needle eye on the upward stroke. So take the needle to the bottom, then as it starts to move up, the hook needs to be 1/16 above the needle eye.

I was thinking the timing of the needle through the inner foot looked off too. Like it's late.

You see this a bunch with old machining tools re-sellers too. They buy a rough lathe or mill at scrap prices, slap a coat of paint on it then sell for decent coin.

On my singer, what I call the primary foot, the one on the back, the shaft has two clamps attached to it. One clamp is for the spring that's on the back of the machine which creates the primary tension for the presser foot and the other is what the hand lift presses on to push the primary presser foot shaft up. I'd probably take off the both presser feet. Unscrew the tensioner thing on the top back, Then see if you can get that rear shaft to lift up and down. You ought to be able to release the clamps and pull it out of the top of the machine but, I wouldn't do that initially. The question is where there's a mechanical jam or if the shaft itself is stuck. When you press up on the hand lift, the inner and outer feet should both lift up. Either one could block you. I don't know that machine so, I can only guess. I have a feeling the problem is in the thing that moved the feet but that's just a guess.

He shows the min-max stitch length on the 105. The 105 and 115 share the same parts book. It seems to be a closer clone to the Juki 211 clone than to the original Singer 211.

I'd say you need to find which machine they cloned when they made the 351. Then see what other companies cloned it. For example, my 211A was cloned by Consew, Juki and Seiko. Juki still sells a model like my 211A so some of the parts are still available from other brands. It looks like REX is a chinese cloner who put their own name on the machines. I have a stack of parts manuals I downloaded from the net so when I want a part I first look up the Singer part, then start looking through the other manuals to see of other use exactly the same parts.